Hi! Thank you for the review.

1) It works this way historically since originally there were no predefined color schemes at all. And this is true only when you are editing Default or Custom color schemes which also were introduced much later. But for Default color scheme to save your changes you can use Set as default. Just one click will do both save and apply the changes.
So meaning of Apply button was defined when it was absolutely logical and I couldn't later change it and break existing users' expectations. But probably I can duplicate Save button near to Apply (and make it even more confusing :)

2) That's a good point. Will try to implement it in the future.

*) There will be a website with more color schemes to choose from soon.